5 replies to this topic

[poppysnoss]

Hello All.

Am trying to tie up loose ends on an essay on cheesemaking and wondered if anyone could help. Does anyone know a recognised method for testing of phage in liquid whey? e.g. If cheesemaking process slows down etc... I fear my brain has turned to cheese tonight.

Any pointers would be muchly appreciated.

[Hongyun]

Hello All.

Am trying to tie up loose ends on an essay on cheesemaking and wondered if anyone could help. Does anyone know a recognised method for testing of phage in liquid whey? e.g. If cheesemaking process slows down etc... I fear my brain has turned to cheese tonight.

Any pointers would be muchly appreciated.

That's a tough one! Hope you have found some info by now...

I've found a patent on the methodology for detection of bacteriophages, but am not sure if it is what you are looking for.

Currently, the approved methods for coliphage detection are detailed in Standard Methods for the Examination of Water and Wastewater, 20th edition as Method 9211 D., ISO Method 10705-2, ASTM Method 4201-96, and EPA Methods 1601/1602. These methods involve the use of agar based media which necessitates difficult and time-consuming temperature control procedures to maintain the integrity of samples and bacterial cultures. Because of the cumbersome, technique-specific nature of the Old Method(s), achievement of reproducible results is difficult for those laboratory technicians who lack experience with the methods or those who do not pay meticulous attention to detail, particularly as it relates to the temperature of the agar.

The approved enumerative methods are based upon the use of a semisolid matrix that functions to immobilize the host bacteria and the infecting phages. The medium must gel so that the bacteria grow within the gel-solid matrix, where they are attacked (infected) by phages present in the sample. When a bacterial host cell is infected with the virus, the virus reproduces within the host until the host cell is engorged with virus particles at which point it bursts and releases the viruses into the environment where they are free to infect new host cells. The consistency of the gel may affect the migration of phage particles in the medium. Those bacteria that are infected release many more phage particles which infect surrounding bacteria so that a clear zone of dead host cells appears in the “lawn” of dense living bacterial growth which covers most of the plate. This clear zone of necrosis is known as a viral “plaque” and the number of visible plaques is used to quantify the number of viruses originally present in the sample.

[Tony-C]

Hello All.

Am trying to tie up loose ends on an essay on cheesemaking and wondered if anyone could help. Does anyone know a recognised method for testing of phage in liquid whey? e.g. If cheesemaking process slows down etc... I fear my brain has turned to cheese tonight.

Any pointers would be muchly appreciated.

I have used the micro method as described by Hongyun.

Also you can set up a test in the laboratory to check the starter activity (in known non contaminated base) using controls and innoculating with the whey. A reduction in the acidity development of the samples innoculated with the whey compared to the control samples would indicate phage activity.

Regards,

Tony

[Slimeron]

Quite complicated question

[Oxxygo]

It’s better to order a finished work, there will be less problems

[Charles.C]

9-year old thread.